1. Field of the Invention
The invention relates to a method for assembling a heat dissipating element and a heat generating element, more particularly to a method for assembling a heat dissipating element and a heat generating element by utilizing a pressure sensitive element. This invention also relates to the pressure sensitive element and a power supplying unit.
2. Description of the Related Art
A conventional electronic product usually needs to have a device in its design for providing power. A power supplying unit (PSU) is one kind of the power supplying devices adopted for supplying power. However, due to the intrinsic property, PSU is a heat source, and thus, there is an extra need for heat dissipating design compared to other electronic products. In the design of the PSU, numerous heat generating elements (such as heat generating diodes) are coupled to heat dissipating plates respectively for lowering the temperature thereof in order to maintain normal operation. As shown in FIG. 1, a conventional method for assembling a heat generating element 41 and a heat dissipating plate 42 is conducted by utilizing a plurality of screws 43. Another possible method to assemble the heat generating element 41 with the heat dissipating element 42 is to utilize a metal or plastic clip.
Insulation between the heat generating element 41 and the heat dissipating plate 42 needs to be considered for preventing interference to functionality of the heat generating element 41. An insulating plate 44 and an insulating washer 45 thus need to be included in the design. Such design leads to a more complicated assembling procedure and is difficult to be implemented by mechanical automation systems. Additionally, it should be noted that the torque for assembling the heat dissipating plate 42, the insulating plate 44, and the insulating washer 45 should not be too much due to their slender designs, so as to prevent breakage thereof that is caused by excessive torque and that affects property of the electronic product.
Besides, the power supplying unit (PSU) has limited inner space. The screw-nut assembly requires more space and increases difficulty in product design. Also, the heat dissipating plate 42 (made of aluminum or copper material) needs to be bored for the screws 43, and metal scraps generated while easily to fall onto other electronic components in the PSU during subsequent processing and may cause other electronic components to malfunction, thereby affecting the quality of the PSU.
Therefore, a thermosetting adhesive layer has been adopted for replacing the screws 43. A process for assembling the heat generating element and the heat dissipating plate via the thermosetting adhesive layer includes the following steps: (1) placing the thermosetting adhesive layer on the heat dissipating plate, (2) placing the heat generating element onto the thermosetting adhesive layer, (3) forcing the heat dissipating element toward the thermosetting adhesive layer to form an assembly, and most importantly, (4) heating the assembly continuously in a heating furnace under a high temperature environment (above 120° C.) for minutes to cause adhesion function of the thermosetting adhesive layer by heat. However, this method requires thermosetting procedure in the heating furnace at a high temperature, and thus facility cost (such as purchasing the high temperature chamber and energy consumption) and production time (heating in the furnace with temperature control increases the difficulty of the mechanical automation) would be increased, thereby lowering the manufacturing efficiency.